Reaction of Laser-ablated Ni Plasma with Methanol Clusters

The gas phase reaction of Ni plasma and methanol clusters is studied by the laser ablation-molecular beam（LAMB） method. Five species of clustered complex ions Ni+（CH3OH）n，NiO+（CH3OH）n，H+（CH3OH）n，H3O+（CH3OH）n，CH3O-（CH3OH）n（n≤25）are observed. Interestingly，the species and sizes of the product clusters vary observably when the plasma acts on the different parts of the pulsed methanol molecular beam. When the laser ablated Ni plasma acts on the head and tail of the beam，the metal methanol complex clusters Ni+（CH3OH）n and the oxidation clusters NiO+（CH3OH）n（n=1-15）together with protonated methanol clusters H +（CH3OH）n are domain. While the plasma acts on the middle of the beam，however，Ni+（CH3OH）1-2 and H+（CH3OH）n along with the mixed methanol-water clusters H3O+（CH3OH）n（n=15-25）turn to be the main resulting clusters. By comparing the intensities and the cluster sizes of NiO+（CH3OH）n with Ni+（CH3OH）n，the formation of NiO+（CH3OH）n is contributed to the intracluster demethanation reaction of Ni+（CH3OH）n and evaporation of several methanol molecules. As the H3O+（CH3OH）n is observed only when the plasma acts on the high density part of the beam，and their intensities are only 0. 5% of the protonated methanol molecule，it is concluded that the species are partially due to the recombination of H+（CH3OH）n and water，which come from the plasma-molecule reaction.